There is known the hydroturbine plant containing two turbines horizontally and coaxially installed in the water conduit and having one power generator (USSR Inventor's Certificate SU No 1280178 issued Dec. 30, 1986). In that power unit the coaxial shafts of the turbines are oriented along the water conduit and are connected by the multiplier located in the pressurized shell in the water conduit center with the generator vertical shaft installed outside the water conduit.
However this leads to the energy usage low efficiency of the water flow coming through the water conduit section. This is stipulated by the fact that the turbines (the propeller type in this case) work alternatively depending on the flow direction and that the shell with the multiplier located in the water conduit effective section center partially closes the working flow directed along the turbine shafts.
The most similar to the invention in accordance with the technical content and achieved result is the power unit containing two coaxially installed orthogonal turbines with the blades of the hydrofoil profile and having the power generator. At that the turbine shafts are oriented across the medium flow, the blades of orthogonal turbines are oriented in the opposite direction relative to each other to rotate the orthogonal turbines in the opposite unchanged directions irrespective of the flow direction coming through the orthogonal turbines. The three-phase power generator is located between the orthogonal turbines (Russian Federation Patent RU No 22245456 issued Nov. 20, 2003).
In this power unit the reaction loads are significantly reduced due to the rotation of the orthogonal turbines with blades of the hydrofoil profile in the different directions, but it's impossible fully to compensate them in consequence of the out-of-phase fluctuating forces acting on the upper and lower orthogonal turbines. As far as the loads acting on the orthogonal turbines are not fully balanced this causes the vibration deteriorating the operation conditions of the power unit and reducing its reliability. Except it the presence of several hydrofoil profiles in each layer of the orthogonal turbine leads to the power efficiency reduction. It is known that single-bladed turbines are the most effective turbines of this class. But single-bladed turbines are not mechanically balanced requiring special masses to balance it.